A huge thank you to everyone who has taken part in the Big Seaweed Search so far, we really value your efforts. Your contributions are extremely important. They are helping us to map seaweed distributions on our shores which is vital information to help us understand the impact of climate change, ocean acidification and non-native seaweeds on our shores. It will take time to pick up change, but already you are helping us to gain invaluable baseline information. Highlights include the wide range of sites surveyed and some fabulous photos. Keep uploading your images as this enables us to verify the results and make them scientifically useable. I’ve put together some key findings here so that you can see how you are doing. If you have not done the Big Seaweed Search survey already, I hope you soon will. If you have already completed a survey please continue to take part and to encourage more people to join in.  Prof. Juliet Brodie, Big Seaweed Search 

Download Juliet’s Results Summary June 2016 – February 2020 (PDF 444KB)

How many surveys have been submitted? 

There have been 376 survey results recorded between 1st June 2016 and 19th February 2020. The number of surveys has increased steadily between 2017 and 2019. 

Where have most surveys been done? 

You can see from the Explore the data page that there are records from England, Wales, Scotland and Northern Ireland although south-west England and south Wales are survey hotspots. This probably reflects ease of access, popular holiday resorts with plenty of rocky shores and Marine Conservation Society staff in place to train trainers and organise group surveys. 

Which areas need more surveys? 

Some areas of the UK coast, such as much of the East Anglian coast, and parts of north-west England have very little or no rocky shore, hence few or no records but seaweeds can be found in these areas on e.g. wooden groynes, concrete structures or other man-made constructions.  

Other areas where there are few or no records but lots of suitable rocky shores include:  

  • parts of the Northern Ireland coast
  • the west and north Welsh coast
  • the north and east coasts of Scotland
  • the Outer Hebrides and 
  • parts of the south coast of England, including the Isle of Wight 

If you live in these areas, have friends or relatives there, or a planning a holiday consider taking part 

Missing photographs 

Sadly around 40% of records were rejected as no photographs were included, which makes it impossible for the Big Seaweed Search team to check and accept the records. Please ensure you include at least one photograph of each seaweed you find during your search.  

What are the most common species of seaweed identified? 

The wracks are the most common group of seaweeds found. These brown seaweeds give many of our rocky shores their characteristic brown zone at low tide and provide important habitat for a variety of crustaceans, molluscs and other species that live in the intertidal zone. The most common species recorded is Knotted Wrack (Ascophyllum nodosum). 

Photograph of Knotted Wrack (Ascophyllum nodosum)

Knotted Wrack (Ascophyllum nodosum) ©Trustees of the Natural History Museum, London / Juliet Brodie

Which seaweeds are most difficult to identify? 

Participants find Dabberlocks (Alaria esculenta) and Wakame (Undaria pinnatifida) the most difficult to identify with more than half of records rejected. Wakame, a robust brown seaweed species, was frequently misidentified as filmy species, including Laver (Porphyra spp. - famous for the Welsh recipe laverbread) which are red, and Sea Lettuce (Ulva spp.), which are green.